Poseidon was the son of Kronos
and Rhea, and the brother of Zeus. He was god of the sea, more particularly of
the Mediterranean, and, like the element over which he presided, was of a
variable disposition, now violently agitated, and now calm and placid, for
which reason he is sometimes represented by the poets as quiet and composed,
and at others as disturbed and angry.

In the earliest ages of Greek
mythology, he merely symbolized the watery element; but in later times, as
navigation and intercourse with other nations engendered greater traffic by
sea, Poseidon gained in importance, and came to be regarded as a distinct
divinity, holding indisputable dominion over the sea, and over all
sea-divinities, who acknowledged him as their sovereign ruler. He possessed the
power of causing at will, mighty and destructive tempests, in which the billows
rise mountains high, the wind becomes a hurricane, land and sea being enveloped
in thick mists, whilst destruction assails the unfortunate mariners exposed to
their fury. On the other hand, his alone was the power of stilling the angry
{102} waves, of soothing the troubled waters, and granting safe voyages to mariners.
For this reason, Poseidon was always invoked and propitiated by a libation
before a voyage was undertaken, and sacrifices and thanksgivings were
gratefully offered to him after a safe and prosperous journey by sea.